It follows the prescription I had adopted from a boilerplate .htaccess file several years ago. But researching the matter a bit, it seems the validator is right, as the proposed change to woff and woff2 in their mime types are found here:

But this is still a bit vague to me. Could you provide a link to (or simple listing of) the precise mime types that should be reported for the standard collection of webfonts? (woff, woff2, eot, ttf, svg, otf). (Perhaps that's already been listed in another posting on the forum...my apologies if it has.)